Please help chem question

Question

If the density of solid tungsten is 19.3 g/cm3 , what is the packing efficiency of W if it adopts a body‑centered cubic unit cell? The molar mass of W is 183.84 g/mol .

Answer 1

In the unit cell of bcc you have 1 central atom and 8 1/8 corner atoms. Since the unit cell side is s and the radius of the atoms in the cell are such that 4r = long diagonal s* sqrt(3), the packing efficiency of the cells are the volume of the 2 atoms/ volume of the cell:

2*(4/3) π(s*sqrt(3)/4)³/s³ = π(8/3)*3^3/2/4³) = .680 or 68%

I didn't use the data. It seems to me that you need more info to arrive at this number from the data. (Like the size of an atom). Maybe I don't understand the question...